FILE - This booking photo released by the Westminster, Colo., Police Department shows Austin Reed Sigg. Sigg, 17, is accused of killing Jessica Ridgeway, who disappeared on the morning of Oct. 5 as she was walking to school. The Colorado Supreme Court Thursday, Feb. 21, 2013, overturned a judge's decision to close a key hearing for Sigg. The court sided with media organizations that argued the judge failed to show that holding the hearing in public would jeopardize Austin Sigg's right to a fair trial or consider other ways to protect Sigg's rights without shutting out the public. Judge Stephen Munsinger in December said he closed the hearing because he wanted to ensure a fair trial and to protect the privacy of victims and their families. (AP Photo/Westminster Police Department)
(The Associated Press)

GOLDEN, Colo. – Colorado prosecutors have added a sexual exploitation charge against an 18-year-old accused of killing and kidnapping a suburban Denver school girl.

Austin Sigg's preliminary hearing is scheduled for Friday in Golden.

He's also charged with murder, kidnapping, sexual assault and robbery in the October killing of 10-year-old Jessica Ridgeway, of Westminster, and accused of attacking a runner.

The Colorado Supreme Court overturned a judge's decision to close Friday's proceedings in which prosecutors plan to lay out their case.

Prosecutors expect the hearing to move ahead, even though a hearing earlier this month was canceled as the media challenged the decision to close it.

Attorneys for the state say they're dropping two charges against Sigg but adding the exploitation charge because of a video of a child found during their investigation.